1. Technical Field
This document relates to devices and methods for enhancing the operations of fluid systems. For example, this document relates to pressure differential relief valves that are well suited for use with medical fluid reservoirs.
2. Background Information
Fluid systems commonly include components such as tubing, pumps, reservoirs, heat exchangers, sensors, filters, valves, and the like. Such components can be connected together in a network to define a fluid flow path. Some fluid systems are open systems, meaning that the fluid flows through the network once and then exits the network. Other fluid systems are closed systems, meaning that the fluid recirculates within the network of components. Fluids are caused to flow in the fluid system using fluid pressure differentials. In some cases, a pump is used to create a pressure differential that causes the fluid to flow within the fluid system. In some cases, a vacuum source is used to create a pressure differential that causes the fluid to flow within the fluid system. In some cases, gravity is used to create a pressure differential that causes the fluid to flow within the fluid system. In some cases, a combination of such techniques is used to create a pressure differential that causes the fluid to flow within the fluid system.
Reservoirs are used as components of fluid systems for various purposes. In some cases, reservoirs are used for accumulation or storage of the fluid. In some cases, the storage of a fluid in a reservoir is used to facilitate a steady outgoing flow of the fluid, despite having an unsteady incoming flow of the fluid. Reservoirs can also be used to facilitate control of the pressure of the fluid within the fluid system. Some reservoirs are completely filled with the fluid, while other reservoirs include an airspace above the level of the fluid in the reservoir.
In some circumstances, the pressure within a reservoir may be higher or lower than the ambient air pressure on the outside of the reservoir. Such pressure differentials can be advantageous when the extent of the pressure differential is within the design parameters of the fluid system. However, in some circumstances the pressure differential between the ambient air and the interior of a reservoir can become greater than intended, and undesirable consequences can result. Such undesirable consequences may include deviating from being in a state of control of the fluid flow, excessive pressure or vacuum levels within the fluid system, damage to the reservoir or another fluid system component, and the like.
Fluid systems are often used in a medical context. Some examples of fluid systems used in the medical context include respiratory systems, anesthesia systems, infusion pump systems, blood transfusion circuits, kidney dialysis systems, extracorporeal membrane oxygenation (ECMO) systems, extracorporeal circuits for heart/lung bypass, and the like. Some such medical fluid systems include the use of medical fluid reservoirs.
As with other types of fluid reservoirs, medical fluid reservoirs may experience a pressure differential between the ambient air and the interior of the medical fluid reservoir that is greater than intended. In some cases, excessive differential pressures can result in undesirable consequences that may damage the medical fluid system. Further, in some such circumstances the undesirable consequences can be risky or inherently detrimental to the health of a patient undergoing treatment using the medical fluid system.